[Danish Mariah SX 18 Owner]

Hi,

Im looking for a new prop for the upcomming season , for my 2006 Mariah SX 18 with 3.0L 135 Hk engine.
I'm looking for a good all round prop, and gain some better acceleration and lover planing speed.
My current prop is the standard Black Max 21 P in aluminum.

Therefore i want to hear what prop you are using on your SX 18 ?

Currently I'm looking on a 3 blade steel prop
Enertia or Vengance maybe in 19"or 20"

my WOT with the black max, 21P is 4400-4500 Rpm.

Best regards

J.W. Danish Mariah SX 18 Owner

[mikeyt]

Most members run a 19" 3 blade prop on that combination with some going to an 18" 4 blade or even a 17" 3 blade. I would suggest a 19" 3 blade SS Enertia prop will be a very good choice as it is a newer design than the Vengance and the blades have in increased rake which should improve bow lift & top end over the rounder shape of the Vengance blades.

btw... i am a bit surprised at how high your WOT rpms are with the 21" black max but it just goes to show that not every identical boat performs the same on the water. We did have a member here quite a while back that successfully used a 23" prop on his 180 Talari which in a normal situation shouldn't work very well at all.

[Andy b]

The high revs may be a result of the condition of the prop Mikey?
Cavitation on a damaged prop does wonders at getting the revs up

I love the Apollo 19" 3 blade s/s prop on my 180 diablo. It is a bit short for my 4.3L, but I love the all round performance I get from it.
It might be a bit long for the 4 banger? depends a lot on how heavy you run your boat....

You have to remember when stepping up from Alu to s/s you need to step down in pitch because the s/s prop has less flex and as a rule is a more efficient prop.

As Mikey said a 17" prop would be a good place to start looking, if you can try a 17" Apollo 3 blade I don't think you will be disappointed. if you do have a good setup then maybe step it up to a 19".

unless you are planning to do a lot of slow speed water sports I'd advise staying away from the 5 blade props on the 3.0L, but if you can stretch the budget to a 4 blade prop then that will give you the best all round performance.
don't forget though that all round means that you are sacrificing performance in offer aspects!

[mikeyt]

Could be a prop condition issue but it may also be a slightly different gearing of the outdrive too. Hard to tell without knowing all of the details. The member who was running the 23" prop on his 180 Talari insisted his prop was in mint condition and the boat had decent jump out of the hole. Normally i'd say BS but w/out actually seeing it i just dont know how to explain it. I do know the 21" 3 blade aluminum that came with my boat was way too sluggish out of the hole but the 20" - 4 blade SS Apollo i installed works great.

I suspect dropping all the way down to a 17" will be too much though. If his rpms were accurate & his 21" prop in good condition, theoretically he will increase his WOT rpms by 800 or so which takes him well over the 4800 max for the 3.0 litre. That 19" Enertia might be just the trick for that boat but ideally it would be good to find a local prop vendor who will let the OP try out a couple of props before he hands over his $$$.

[Danish Mariah SX 18 Owner]

Thanks, for your input,
its makes it easier for me to decide :-)

i have now got the chance to try out the Enertia SS in 19" and 20" so i plan to take one of the first days in the season
and do som systematic testing of the 2 sizes compared with my standard 21P black Max.

I will post the results when the test is completed.

Best regards

J.W